Highly selective nicotinohydrazide based 'turn-on' chemosensor for the detection of bioactive zinc(II): Its biocompitability and bioimaging application in cancer cells

A novel optically active (E)-N'-(5-allyl-2-hydroxy-3-methoxybenzylidene) nicotinohydrazide (receptor 3) was synthesized by simple Schiff base condensation of 5-allyl-2-hydroxy-3-methoxybenzaldehyde with nicotinohydrazide. The ability of receptor 3 was investigated for the selective sensing of cations by chromogenic and fluorogenic technique. Receptor 3 showed highly selective response for Zn2+ ions in the binary mixture of acetonitrile/water ( 50:50, v/v) and possessed no interference from any of the potentially competing cations. Upon additions of Zn2+, the fluorescence intensity of the receptor 3 showed significant enhancement at 517 nm due to the chelation-enhanced fluorescence ( CHEF) effect. The receptor 3 showed a good linearity for Zn2+ ion with the detection limit down to 4.35 nM. With negligible toxicity towards live cells, the receptor 3 could be successfully employed to monitor the Zn2+ ions in live A549 cells. (C) 2018 Elsevier B.V. All rights reserved.